Talk:Paper - The measurement of diaphysial growth in proximal and distal directions (1916)

THE MEASUREMENT OF DIAPHYSIAL GROWTH IN PROXIMAL AND DISTAL DIRECTIONS. By Kenetm H. Dicsy, M.B., F.R.C.S., Professor of Anatomy, University of Hong-Kong.

THE nutrient foramen of the shaft of a long bone transmits the vessels which provide blood for the ossifying cartilage during growth, for the. resulting bone, and later for the medulla. The original artery which accompanies the initial invasion of the primitive cartilaginous rod by osteoclasts and osteoblasts enlarges and persists as the nutrient artery. Bone is deposited round the vessel, thus forming a permanent track which traverses the compact tissue in a most oblique direction for from one-half to two inches and more, according to the particular bone. The nutrient foramen in the adult is only the external opening of the nutrient canal.

It follows from its manner of formation that the nutrient canal always points towards the oldest part of the shaft of a long bone. It is more accurate to say that the canal points towards the site which the oldest part of the bone would occupy were it not that the osseous tissue first formed is subsequently absorbed in providing the medullary cavity. Indeed, but for this absorption the bottom of the canal would be formed by the very earliest deposit of bone.

If the various long bones of the body are sawn longitudinally so that the nutrient canal lies in the plane of division, the initial point of ossification may be easily determined, for it corresponds to that point in the centre of the medullary cavity which is reached by an imaginary prolongation of the nutrient canal. The site of initial ossification having been determined, it becomes easy to measure the precise lengths of bone which are formed from the two growing ends of the diaphysis.

The result of such an examination of the principal long bones of the human body is as follows :—

Formed from Proximal Formed from Distal End End of Diaphysis. of Diaphysis. Name of Bone. “a . .

Length in, Proportion | rongth in | Proportion

Inches. | Diaphysis. Inches. Diaphysis.

| per cent. per vent. Femur . . . 5 31 11 69 Tibia 2 sl, 73 57 5B 43 Fibula 2. 74 60 5 40 Clavicle . . . 34 | 62 2 38 Humerus : . 93 81 24 19 Radius . . . 2 25 6 75 Ulna . . . 12 | 19 78 81 188 The Measurement of Diaphysial Growth

Notes.

1. These bones were taken from different bodies. A thorough examination of a large series of each bone is desirable to provide reliable averages.

2. It is generally assumed that the obliquity of the nutrient canal results from the fact that whilst a bone grows in length chiefly from one end, the vessel, from which the nutrient artery springs, grows equally throughout its

FEMUR AB = 5 wnenes BC = 11 wncnes

TIBIA AB = 75 iecnes 8 C= 53 wees

FIBULA AB = 75 wcnes BC=$5 wenes

HUMERUS AB=$95 wenes BC =2: wenes

RADIUS AB=2 wncnes 8B C=6 wnenes

en 28

ULNA AB=12 wenes BC= 73 wenes

cravicre (Not figured) AB=33 incnes BC=$2 wenes

Tracings of longitudinal bone sections. A, upper end of diaphysis; B, initial site of ossification ; C, lower end of diaphysis.

length. Relative changes in the position of the proximal end of the artery, however, might also be a factor in determining the degree of obliquity. But, anyway, the canal leads inwards to the initial site of ossification.

That this is so is confirmed by the presence of the nutrient foramina in very young bones—before the fourth month of foetal life; and also in the case of the adult femur where, when two foramina are present (as not infrequently happens), the nutrient canals have different obliquities, so that when prolonged they converge on almost the same point in the medullary cavity.